The invention relates to a two-directional scraper intended for fluid carrying pipes. The invention is notably well-suited to withstand both chemical attack and abrasion. When the same pipe is used for successively delivering different fluids, it is well-known to use scraper plugs to separate the fluids while cleaning the walls of the pipe. These scrapers can also be displaced all along the pipe in order to remove, at regular intervals, the deposits that may have formed on the inner walls.
Document EP-376,796 describes a two-directional scraper whose elastomer wear rings do not have a sufficient chemical and abrasion resistance for certain applications.
In order to overcome this drawback, it is advantageous to combine mechanical reinforcing elements with sealing and scraping elements.
The present invention thus relates to a two-directional scraping device intended for a fluid delivery pipe. The device comprises at least one thin disk made of polymer stiffened by means of reinforcing elements, and the disk is divided into petals by at least two radial slots whose length is smaller than the radius of said disk, said radius being substantially greater than the inside diameter of said pipe.
A second thin disk can be superposed on the first one so that the slots of the two disks are arranged in staggered rows in relation to one another.
Two sealing and scraping assemblies consisting each of at least one thin disk can be connected by a shaft and two end parts so as to space said two assemblies out by about the length of said shaft.
The thickness of the assemblies can be smaller than the space contained between the shaft and the end parts so that said thin disks can bend in both directions.
The scraping and sealing assembly can also comprise at least one non-reinforced polymer disk.
The reinforcing means can be metallic.
In a variant, the reinforcing means can be made of a composite material.
The reinforcing means can consist of a radially slotted disk.
The reinforcing means can consist of a disk slotted like the polymer scraping and sealing disk.
The reinforcing means can be embedded in the polymer disk.
The reinforcing means can be pressed on the polymer disk.
The polymer can be a polyamide, polyethylene, fluorinated polymer type thermoplastic, for example PEUHMW, ETFE, FEP, PVDF, ECTFE, PFA, PTFE, PEEK, and mixtures thereof; a thermosetting material such as epoxy or polyurethane; an elastomer.
The polymer can be filled with an abrasion-resistant material. 5
The invention also relates to the application of the device for scraping and/or separation of two fluids in a pipe delivering fluids chemically aggressive towards elastomers.
The invention is thus based on a concept using different means to fulfill two main functions:
polymer elements fulfilling scraping, sealing and abrasion resistance functions on contact with the pipe,
reinforcing means, for example made of spring steel or composite, to provide sufficient stiffness for maintaining in contact with the wall of the tube, in particular at bends and during changes in the scraping direction.